In exposure devices such as scanning steppers or steppers used in lithography processes for manufacturing semiconductor devices and the like, it is necessary to manage a plurality of sets of exposure conditions such as a dose quantity (an exposure quantity), a focal position (a defocus amount for the substrate to be exposed relative to an image plane of a projection optical system), an exposure wavelength, and the like with high precision. To do so, it is necessary to expose a substrate using an exposure device and evaluate the actual exposure conditions of the exposure device with high precision using a pattern or the like formed on the exposed substrate.
As a conventional method for evaluating a focal position in an exposure device, for example, a pattern for evaluation in a reticle is illuminated by illumination light whose principle ray is tilted. A substrate is exposed with an image of the pattern at a plurality of shots while varying the height of the substrate in sequence by a stage. A horizontal shift amount of a resist pattern obtained through post-exposure development is measured, and the focal position during the exposure of each shot is then evaluated on the basis of the measurement results (see Patent Literature 1, for example).